Multi-Query Path Planning for Exploration Tasks with an Unmanned Rotorcraft

Florian Adolf
2012 Infotech@Aerospace 2012  
This paper presents an online multi-query path planner for exploration tasks planned onboard an unmanned helicopter. While the desirable properties of roadmaps can be exploited in offline path planning, the dynamic nature of exploration scenarios hinders to utilize conventional roadmap planners. Hence, the presented path planning approach utilizes a deterministically sampled roadmap which is dynamically indexed in real time. To address situations of partial terrain knowledge, the roadmap can be
more » ... extended from its a priori dimensions towards locations of unknown terrain that are outside its original, a priori boundaries. The multi-query property of the planning system allows for combinatorial optimization such that a rapidly acting decisional autonomy is achievable during exploration flights. D*-Lite is used as dynamic heuristic path searcher in order to re-plan efficiently. Inspired by the original work on this path search algorithm, the roadmap graph is augmented with an exploration vertex which steers the exploration behavior of the vehicle. As a result, the presented roadmap guides an unmanned rotorcraft through a priori unknown urban terrain in real time. Nomenclature ARTIS = Autonomous Rotorcraft Testbed for Intelligent Systems CDF = Cumulative Distribution Function D*-Lite = Heuristic path search algorithm with efficient re-planning for dynamic environments d clear = Minimum clearance distance of the vehicle from the closest obstacle [m] d sensor = Maximum detection distance of the obstacle sensor [m] FOV = Field of View of a sensor LIDAR = Light Detection and Ranging range measurement sensor ("laser scanner") MiPlEx = Mission Planning and Execution framework for ARTIS NED = Local north (x ), east (y ), down (z ) coordinate system V kmax = Maximum magnitude of the velocity command vector V k [ m s ] C = Configuration space of the vehicle C f ree = All reachable vehicle configurations with C f ree ⊆ C C obst = All unreachable vehicle configurations with C obst ⊆ C f ree = Number of collision free edge connections to neighbor samples of a vertex neighbors = Number of neighbor edges connections within a bounded Euclidean range in the roadmap local = Local visibility of a vertex f ree neighbors [%]
doi:10.2514/6.2012-2452 dblp:conf/itaero/Adolf12 fatcat:dqslvj2rurck5imjqjnvdps47y